The specific aims of this proposal are to study some features of the biosynthesis of complex glycoproteins found at the surface of human cells, the HLA-A, -B and -D antigens including both the glycan and polypeptide moieties of these antigens. In particular, we will study 1) the composition and structure of the carbohydrate moieties of the heavy chain of the HLA-A and -B antigens and of both chains of the HLA-D antigens, 2) the biosynthesis of these antigens in vivo utilizing both normal human B lymphoblastoid cell lines and several mutant cell lines which have been obtained, 3) the biosynthesis of these antigens in vitro utilizing mRNA isolated from the B lymphoblastoid cell lines with cell-free translation systems and subcellular fractions capable of sustaining glycosylation reactions and 4) the biological and chemical properties of deglycosylated HLA antigens in several systems that are available.